Calculations within Repeating Section

I have a repeating section that has 3 fields, Start Date(Date and Time) and End Date(Date and Time) and Hours(Calculated Value). What I want is for this calculated value to automatically populate with the result of (End Date - Start Date). Outside and below the repeating section, there's also a calculated value that displays the Total of all hours under the repeating section.

Additional Info: Maybe this is not the best approach for my problem. What I am trying to achieve here is a form that will be used to calculate Total Overtime worked for employees. Each record should be in a new line with Date, Start Time, End Time and Total Hours worked. The reason why I chose repeating section is because records will vary per user.